Use of dentists  pattern-plates



UNITE STA T FMC USE OF DENTISTS PATTERN-PLATES.

Specification of Letters Patent No. 20,754, dated June 29, 1858.

To all whom it may concern.'

Be it known that I, VILLIAM M. WEIGHT, of the city of Pittsburg, county of Allegheny, in the State of Pennsylvania, have invented a new and Improved Mode of Casting Plates to Sustain Artificial Teeth in the Mouth, which I call the Maxilla- Type Process, (maxilla, the jawg) and I do hereby declare that the following is a full, clear, and exact description of the construction and operation of the same, reference being had to the annexed drawings, making a part of this specification, in which- Figure 1 is the pattern and teeth molded in plaster ready for pouring. Fig. 2 is the metallic model and counter model. Fig. 3 is the pattern plate with teeth attached ready to be tried in the mouth. Fig. fi is the pattern plate and teeth placed on the plaster model with the outer surface and coronal extremities are covered with plaster. Fig. 5 is a transverse section of Fig. 6. Fig. 6 is an impression of the upper jaw, with the ridge A running along the posterior e ge.

The nature of my improvement consists in using a material for the pattern that can be readily rolled to any desired thickness, sufliciently strong when modeled to the cast (as hereafter described) to be handled and have the teeth attached to try them in the mouth (Fig. 3) without danger of alteration or change in the pattern; and also to possess the quality of melting at a low degree of heat.

My method consists 1st in taking the impression of the jaw in the usual way (Fig. 5). Then take a thin strip of wax and lay it on the edge of the line you intend the plate to extend. (let. A, Fig. This strip of wax should be beveled; the thin edge lying toward the front of the mouth, and rising, gradually backward and to a thickness, to be regulated by the softness of the vault of the palate. The object of this I consider a very important one, and to the practical dentist an indispensable one. It secures in the castplate a turned up edge, which in gold or silver plates is always done with the pliers just before the plate is inserted, but which cannot be done in a cast plate by reason of its brittleness. Plaster mixed with water is then poured into this impression in the usual way, giving the plaster model of the jaw superior or inferior niaXillary as the case may be. I then with -liard metal as is used for swaging gold or silver plates. I make the metallic model (Fig. 3) with tin and antimony, in the proportion of G of tin to t of aiitimony, the counter model of lead and tin in the proportion of 8 of lead to 2 of tin. This makes a smooth, hard model and is readily melted over an ordinary fire. )Vith these castings I strike up a pattern out of rolled metal made with 6 parts tin, 3 parts lead, and l part bismuth, the plateA to be rolled to the thickness I desire the cast plate for the mouth to be.

By this process an accurate pattern can be obtained to cast from, fitting accurately into all the irregularities of the gum and palate. Having such a pattern we can cast lighter and more accurate plates than by any other process-no superabundant metal at points where not needed. This pattern thus made, is tried in the mouth, and trimmed to the desired size. The arrangement of the teeth on this pattern plate is the same as is pursued with gold or silver plates struck up for the mouth. Vax is placed on the alveolar ridge-the articulation is taken-the teeth are attached, and when arranged can be placed in the mouth, because the plate pattern thus made will have all the suction that is obtained in gold or silver plates struck up, thus giving the operator an opportunity of adjusting the teeth properly, in reference to the set and expression. W'hen all this is effected the pattern with the teeth (Fig. 3) is placed on the plaster model. The front of the model being well oiled, plaster mixed with water is poured around the front of the teeth (Fig. 4) just as is done when teeth are to be backed with gold or silver. Nhen the plaster has set and the wax taken off which held the teeth to the pattern, they are backed with waxin form and shape just as you would with gold or silver, only making the wax somewhat thicker. Then this is done place a gate at one end or side of the plate (Fig. 1, let. B, B) with a vent on the opposite side, then oil the back part of the plaster model, and pour plaster on the remaining part of the cast enveloping pattern plate, teeth and all in plaster. When the plaster has set, part the casts, and put them on a stove or in a furnace of moderate heat, let

them dry slowly, turn the mold having the pattern plate and teeth in it-with the plate neXt to the heated surface-and when the plaster becomes dry and the heat continued the pattern plate will by reason of the composition of the metal melt and run out. The wax will be absorbed in the plaster. r1`he two parts being well dried, the pattern plate out, the waX absorbed, &c., the teeth should be examined to see whether they have moved from their proper position or loose. If they have, they should be readjusted and held in their position by a little fluid plaster placed at some convenient point. Now place the two parts together. rfake some of the approved metals for casting plates for the mouth, place it in a small ladle with a small lump of pure beeswax along. The waX prevents oxidation of the metal while melting and also, in a most remarkable degree assists in the perfect flowing of the metal into the cast and insures a perfectly smooth and accurate casting. t also regulates with me the temperature at which the metal should be poured, which is ust when the wax takes lire. After pouring hold the molds for a few moments until the metal hardens-then part and proceed to finish in the usual way. in form and thickness to the pattern plate used to retain the teeth, &c.

For parts of sets or models that cannot be molded to make metallic models, gutta percha warmed in water and rolled to a proper thickness can be used with advantage for pattern plates. It should be warmed in water and pressed on the plaster model and when cold can be taken off and used just as described with the metallic pattern plate.

Having thus fully described the nature of my improvement in casting artificial dentures, I wish it to be distinct-ly understood that I make no claim to the casting` of such work-the process being described in the Dental Journal of 1852; but

`W hat do claim and desire to secure by Letters Patent, is-

T heuse of metallic pattern plates or their equivalent, made as described, for the purpose herein set forth and specified.

W. M. VRIGHT.

'Vitnesses J. D. OWENS, THOMAS MAXWELL. A

The plate thus cast will be 

